Battling America’s ‘Dirty Secret’: Climate Change Raises the Risk from Failing Sewage Systems.

by Sarah Kaplan (Washington Post) ... (Catherine Coleman) Flowers has a vision for a better septic system. It’s cheap to buy and easy to run. It’s equipped with sensors that can monitor for signs of pathogens, including the coronavirus. Instead of allowing sewage to seep into the ground, the system separates waste into its component parts, which can then be recycled.

“Waste could provide a lot of solutions,” Flowers said, “if we just learned to think about it differently.”

They met five years ago at a conference on wastewater issues. Chandran, an environmental engineer at Columbia University, was struck by how similar Lowndes County’s waste problems were to those in his native India. Flowers remembered hearing about Chandran’s research and thinking, “This is the technological solution we need.”

An expert in the chemical and biological processes that remove contaminants from waste, Chandran had helped to improve sewage systems from D.C. to Denmark. But he knew those advances weren’t helping the millions of people who live beyond the reach of pipes.

Kartik Chandran, an environmental engineer at Columbia University, has partnered with Flowers to devise a toilet system to clean the components of sewage on-site for repurposing. (Columbia University)

He also thought it was a mistake to refer to sewage as “waste,” when it is actually rich with potentially valuable resources: nitrogen, phosphorous, organic material. He and his colleagues started working on ways to scale down big-city sewage technology and upgrade treatment processes, turning every septic tank into its own miniature “resource recovery system.”

Chandran’s lab is a maze of plastic tubes and burbling tanks, each jug containing some mix of wastewater and chemicals. In one prototype, a film of bacteria takes the nitrogen out of synthetic urine; it’s been running for more than a decade, he said, and takes almost no energy to function. With another experiment, Chandran is trying to find the right combination of microbes that will turn organics from fecal sludge into fuel, which could theoretically be used to help power homes. When all these processes are integrated, he said, the heat and acidity produced through decomposition will kill off dangerous germs, and the water that comes out the other end will be clean enough to be recycled in washing machines or cooling systems.

But the most important metric of success, he said, is whether the people who need the system actually will use it. That’s where his partnership with Flowers comes in.

Through the new Wastewater Innovation and Environmental Justice lab, representatives from Lowndes County, Navajo Nation and other affected areas will be part of the design team for the high-tech septic tank. The lab has initial funding from a sustainable finance company, and Chandran is applying for more grants. Once the coronavirus pandemic recedes, engineers from his lab will move into partner communities while they work on improving the system.

Different places will have different needs, Chandran noted. Rural communities like Lowndes County might benefit from a tank that extracts nitrogen and phosphorous to be used as fertilizer. In the desert Southwest, it might be more important to purify to drinking quality the water that comes out of the tanks. READ MORE